Norman Finkelstein is an unpopular man. Norman Finkelstein has always been an unpopular man, but for decades he had a cult following among leftists and supporters of the Palestinian cause. Since coming out in 2012 against the Boycott, Divestment, and Sanctions (BDS) movement, however, he has alienated his core followers. A few years ago, Finkelstein tells me, he made $40,000 in speaking fees from 80 talks to Palestinian Solidarity groups around North America. “This past year when I went to my accountant ... he said, 'I think you have a mistake here, it's only $3,000.' I said, 'No, it's not an error.' He said, 'What happened?' And I thought to myself: Am I going to explain to him BDS?"

Finkelstein, 61, is wearing a T-shirt and shorts in his Coney Island apartment, where he lives alone. He has just completed a year teaching international law, the Israel-Palestine conflict, and political philosophy at Sakarya University in Turkey. He’s working on a book with the Dutch-Palestinian scholar Mouin Rabbani on how to solve the conflict. It includes a chapter on BDS, a movement to divest from Israel over its treatment of Palestinians that began a decade ago, on July 9, 2005. But he hates traveling and is angry that he can’t find a teaching job in North America or Europe. "There was a lot of resentment on my part, because I live probably within an hour of 15 or 20 universities," he says. Instead, "I had to board a plane every month, and go to Turkey, and it's basically about an 18-hour trip each way."

Finkelstein was unemployed for seven years after being denied tenure at DePaul University in 2007 following a campaign against him, led by Harvard’s Alan Dershowitz, that drew nationwide attention. He says there were "huge gaps" in his day during this time, and "a lot of sleep." "It has been a very depressing period,” he says, though he also found time to write books on Israel-Palestine and on Gandhi. “I would say it was squandered years.”

Finkelstein’s longtime critics probably consider his previous two decades even less fruitful. He first gained attention in academic circles in 1984 for exposing the poor scholarship of From Time Immemorial, a book by journalist Joan Peters. The book claimed that Palestinians didn’t exist—that they lacked deep roots in historical Palestine but in fact were Arabs who swarmed the deserted land only once Zionists began developing it in the late nineteenth century. From Time Immemorial was a best-seller initially praised by everyone from Saul Bellow to Elie Wiesel to historian Barbara Tuchman, who called it “a historical event in itself.”

At the time, Finkelstein was an unknown graduate student. He had grown up in Brooklyn, the son of Holocaust survivors who, he has said, mentally “never left the camps.” His parents were eternally grateful to the Soviet Union for having liberated them from the Nazi camps, and they inculcated him with a political radicalism that he has never shed.

Finkelstein’s tendency toward political fanaticism first emerged in his adolescent adoration of Chairman Mao’s China. He hung Communist propaganda posters on his bedroom wall, studied with the world’s leading Marxist scholars in Paris, and would espouse the virtues of the socialist paradise Mao was building to anyone who would listen. When his shoes were stolen while he was napping in the study lounge at university, he scolded his classmates that “this would never happen in China.”

But when Mao’s political heirs, the Gang of Four, were overthrown to mass celebration in 1976, Finkelstein realized that he had been a willing dupe of Communist propaganda. Devastated, he spent three weeks in bed depressed. He was disillusioned by his own self-deception, a quality he thinks radical activists can be particularly susceptible to.

He became politically reengaged by opposing Israel’s invasion of Lebanon in 1982. But wary of being duped again, he spent an entire summer in the New York Public Library combing through the population records of historical Palestine and comparing them to Peters’s book. He discovered that From Time Immemorial was, as the Israeli historian Yehoshua Porath eventually put it, “a sheer forgery.” Finkelstein published his findings, and Peters’s book is now widely considered, as David Remnick wrote in the New Yorker a few years ago, “thoroughly discredited.” Finkelstein’s reputation was made.

Throughout the 1990s, Finkelstein became a prominent defender of the Palestinians and a relentless critic of Israel and what he called “the Holocaust Industry.” Culminating in his 2000 book of that name, Finkelstein claimed that Israel exploited the Holocaust to excuse its crimes against the Palestinians, and that claims by the lawyers of Holocaust survivors that they deserved compensation from Swiss banks for wealth expropriated during World War II were part of “a shakedown” by “a repellent gang of plutocrats, hoodlums and hucksters.” Finkelstein was called an anti-Semite and, in the memorable words of former New Republic literary editor Leon Wieseltier, “poison, he’s a disgusting self-hating Jew, he’s something you find under a rock.”

Along with Edward Said and Noam Chomsky, Finkelstein was the most prominent American defender of the Palestinians, a “rock star of the pro-Palestinian movement,” according to Al Jazeera. But unlike Said, he is Jewish, and unlike Chomsky, he seemed obsessed with only one issue: Israel. He called it a “lunatic state” and “satanic.” He called Alan Dershowitz’s The Case for Israel a fraud and charged the pro-Israel activist with plagiarism, which led the famously contentious lawyer to publicly oppose Finkelstein’s tenure bid. The battle over Finkelstein’s tenure status became a national dispute over academic freedom in the eyes of his fans. DePaul students staged sit-ins and even hunger strikes, but to no avail.

For the next five years, Finkelstein spent most of his time in his Brooklyn apartment (although he took time out to be banned for ten years from Israel after visiting Lebanon and declaring solidarity with Hezbollah). “I’m very much a homebody,” he says, and his life seems a lonely one. His bookshelves detail his life’s twin fixations: one is devoted to works of Communist theory, and two others to books on the Middle East. He wrote books on Israel’s 2008-9 invasion of Gaza and on the estrangement of American Jews from Israel, and he continued to tour campuses as a hero to Palestinian solidarity groups. If they were unproductive years, Finkelstein could at least take solace in knowing his martyrdom was appreciated.

All that changed in February 2012. Finkelstein had become concerned with the international pro-Palestinian community’s embrace of BDS—it has become the preferred solution among activists on campuses and much of the Palestinian diaspora. He feels the position is inconsistent with international law’s recognition of Israel’s existence. In an interview with a French pro-Palestinian activist, Finkelstein declared his opposition to BDS—and did so in the same inflammatory language he had been using for decades to describe Israel and its supporters. “I loathe the disingenuousness—they don’t want Israel [to exist],” he said. “It’s a cult.” He had spent his time in a self-deceptive Maoist cult, he said; he wouldn’t do it again. He accused BDS activists of “inflating the numbers” of Palestinian refugees and “want[ing] to create terror in the hearts of every Israeli” rather than resolve the conflict. “I’m not going to tolerate what I think is silliness, childishness, and a lot of left-wing posturing,” he said.

The reaction among his supporters was disbelief and fury. He was called a “Zionist bully,” an “angry right wing pundit,” someone “who opposes rights for all Palestinians,” and, in what was surely the biggest insult to him, a “comrade at heart with Alan Dershowitz.” Finkelstein’s primary source of income, his speaking fees, plummeted. He has since repeated his criticisms, and as a result has become nearly as unwelcome among supporters of Palestinians as he is among Israeli partisans.

Indeed, the response from Israel’s supporters to Finkelstein’s comments ranged from glee at the infighting among Palestinian advocates to puzzlement at what they see as Finkelstein’s newfound reasonableness. “I don’t understand—he consorts with Hamas, he’s hostile to Israel in every possible way, and yet he comes up short on this one,” says Daniel Pipes, president of the Middle East Forum, a conservative think tank.

BDS advocates say that the campaign for a two-state solution has brought nothing for Palestinians but a more entrenched Israeli occupation of their lands. They chalk up Finkelstein’s old-fashioned support for a two-state solution to his age or desire for attention. “There was a time when Norman Finkelstein was one of the loudest and one of the only voices on this issue,” says Rania Khalek, an editor at The Electronic Intifada. “He’s done incredibly valuable work, but with BDS growing, other people besides him are at the center who are most important.” “There are a number of people among an older generation of activists and advocates who were not quite prepared by the younger caste who have a strong message but differences in tactics,” says Yousef Munayyer, a leading Palestinian-American activist.

Indeed, Noam Chomsky has also come out against BDS in support of Israel’s existence. He calls the attacks on Finkelstein “completely uncalled for, indeed outrageous.” He says that Finkelstein “had cogent and rational arguments” and “has done more for the Palestine cause than all those who launched these disgraceful attacks combined.” Hussein Ibish, an Arab-American scholar who supports a two-state solution, says that “Finkelstein and Chomsky have enough experience and have their ear to the ground to see that the one-state effort is quixotic. BDS’s hysterical reaction to Finkelstein was inevitable, because it’s much closer to a religion than it is to a political idea.”

Finkelstein is unrepentant. "I made significant errors of political judgement, and I would think, more or less, the same could be said about a lot of the grassroots activists in the BDS movement," he says. "They're committed, they've achieved many significant and impressive results, but I think there are also errors of judgement, and I don't think it's my responsibility to just be a cheerleader."

Finkelstein is aware of the fact that he is more isolated than ever. If it’s not something he’s happy about; it’s something he’s prepared to live with.

"Sometimes I carry this reputation of being a kind of wild man, but actually everything I say and do is quite calculated and careful, in public," he says. Then he adds, "I'm less reticent to take chances than most other people."

This article has been updated to correct several discrepancies between quotations attributed to Finkelstein and the audio of the author's interview. A previous version also misstated his age.